1. Field of the Invention
The present invention relates to a modular IC handler for inspecting the performance of a modular IC, and more particularly, to a modular IC holding device in a modular IC handler for holding a modular IC when loading the modular IC from a cassette to a test socket or unloading the modular IC, of which a test has been completed, from the test socket to an empty cassette.
2. Discussion of the Related Art
In general, the modular IC is provided with a plurality of ICs and components soldered on one face or both faces of a circuit board to form an independent circuit, which is mounted on a main circuit board for extension of a capacity or a function. Since such modular IC has a value added thereto higher than individual ICs, IC manufacturers develop and sell modular ICs as a main product. Because the reliability of the modular IC product is very important, the modular IC products pass through a strict quality control process, to forward only products that have good quality, and to correct or discard products that are determined to be defective. There has been no device which automatically loads a completed modular IC on the socket, conducts a test, automatically classifies the modular IC according to a result of the test, and unloads the modular IC into the cassette. Therefore, a worker should pick-up the modular IC from the cassette one by one manually, load it into the socket, conduct a test, classify it according to a result of the test, and unload it into an unloading cassette. Thus, the modular IC testing work has a low working efficiency, that results in a low productivity. Eventually, the applicant has developed a handler which picks up a completed modular IC in a cassette by means of a picking up means, automatically loads it into a socket, conducts a test, automatically classifies and unloads it into an empty cassette according to a result of the test (Korea patent laid open Nos. 97-072236 and 97-072275, and Korea utility model laid open No. 97-059865).
FIG. 1 illustrates a front view of a loading part in a modular IC handler shown in Korea patent laid open No. 97-072275 of the applicant, and FIG. 2 illustrates a side view of the loading part shown in FIG. 1, provided with a carrier 2 coupled to a robot shaft 1 for moving in up and down directions, a lifting piece 3 coupled to the carrier 2 for moving in up and down directions, and at least one modular IC pick-up means under the lifting piece on both sides thereof for moving in up and down directions in picking up a modular IC 4 in a cassette or a socket (not shown).
The modular IC pick-up means will be explained. There is at least one lifting block 5 movable in up and down directions under the lifting piece 3. There is a first cylinder 6 for moving the lifting block 5 between the lifting piece 3 and the lifting block 5 such that the lifting block 5 moves for a preset stroke in up and down directions according to the operation of the first cylinder 6. The aforementioned lifting block 5 is provided with a holder for holding a modular IC in a socket or a cassette.
A background art holder will be explained with reference to FIGS. 3 and 4.
There are second cylinders 7 fixed to both ends of the lifting block 5, and a cylinder for moving in a horizontal direction. There is a slider 8 fixed to a rod 7a of each of the second cylinders movable according to a movement of the second cylinder, and there is a finger 9 fixed to each of the sliders in opposite direction for holding both sides of a board of the modular IC. And, one of the fingers 9 has a contact sensor 10 for determining holding of a modular IC in driving the second cylinder 7. FIGS. 4 and 5 illustrate the second cylinder 7 for moving the finger 9 in more detail. The slider 8 is provided with V-grooves 8a in both sides thereof for stable movement of the slider 8 fixed to the rod 7a, and the second cylinder 7 is also provided with V-grooves 7b opposite to the V-grooves 8a in the slider 8. Roller bearings 11 are inserted between the opposite V-grooves for minimizing a contact friction in movement of the slider 8. The second cylinder 7 is formed divided in two parts, body 12 and cover 13, for assembly of the slider 8 with screws 14.
The operation of the background art holder will be explained.
The lifting block 5 moving in up and down directions according to the operation of the first cylinder 6 is located at a top dead point when the holder is not at hold of a modular IC, and the fingers 9 which move oppositely in a horizontal direction according to operation of the second cylinder 7 are wide open to opposite sides greater than a modular IC, i.e., a width of the board. And, as shown in FIG. 2, in the case of the handler with a plurality of lifting blocks 5 for handling a plurality of modular ICs 4, the lifting blocks 5 on the right are spaced at short intervals for holding modular ICs before test in cassettes spaced at short intervals and the lifting blocks 5 on the left are spaced at wide intervals for holding modular ICs in test sockets spaced at wide intervals. When the first cylinders 6 are operated to lower the lifting block 5 for holding a modular IC, the fingers 9 are positioned on both sides of the modular IC, with the fingers 9 wide open. Upon operation of the second cylinders 7 on the lifting block 5 by means of compressed air supplied through the compressed air hose, the wide open fingers 9 come closer to each other to hold the modular IC from both sides. Only when the lifting block 5 is lowered by operation of the first cylinders 6 and the contact sensor 10 at one side of the finger 9 pressed by the modular IC to sense the modular IC, the second cylinders 7 on the lifting block are operated to hold the modular IC; if not, the second cylinders are not operated. When the lifting blocks 5 are lowered and the modular ICs in cassettes or sockets are held, the first cylinders 6 are operated again, to elevate the lowered lifting block 5, completing picking-up of the modular IC.
However, the background art device has the following problems.
First, an upper surface of the finger 9 is brought into close contact with an underside of the slider 8 in assembly of both. Therefore, the lack of a reference surface may cause an assembly with the finger slanted, frequently impeding holding of the modular IC at right positions.
Second, as the body 12 of the second cylinder 7 is distorted at processed portions when the body 12 is heat treated, the body 12 of the second cylinder in general has not been heat treated while the cover 13 only is heat treated. Accordingly, when the holder is used for a long time, the body 12 of the second cylinder 7, which is not heat treated, is seriously worn down as the slider moves due to friction with the roller bearings 11, causing an erratic operation of the second cylinder to drop a modular IC held by the fingers 9 in the middle of operation.
Third, since the sensor 10 sensing existence of a modular IC to hold is a contact type, there have been cases when the sensor can not sense the modular IC due to wear down from prolonged use.
Fourth, the two lengthy compressed air hoses 15 connected to each of the double-acting second cylinders 7 interfere with movements of the lifting blocks 5 and the second cylinders 7.